How B Vitamin Nutrient Deficiencies Affect Your Mental Health

Published on: Apr 30, 2023

Contrary to popular belief, nutrient deficiencies CAN affect your mental health. In fact, a number of factors affect our mental health including diet, lifestyle, genes, hormones, brain chemistry, and even life experiences (helloooo, trauma).

So, yes, certain nutrient deficiencies can affect our mental health by impairing the function of our brains, thus increasing our risk of developing mental health concerns such as anxiety and depression. For instance, several vitamin deficiencies that have been associated with reduced psychological well-being include seven of the eight B vitamins. Not only can these B vitamin deficiencies impair the function of our brains, but they can also negatively impact our energy levels. If you are or have experienced depression, you know firsthand how debilitating extreme fatigue can be! Fatigue was one of the most frustrating experiences I’ve had as someone who lives with Hashimoto’s thyroiditis and has also experienced bouts of depression.

In this blog post, we’ll look at how having a B vitamin nutrient deficiency could affect your mental health and well-being, and how treating these deficiencies with the right foods (and in some cases, supplements) can help to reduce symptoms of depression and anxiety.

B Vitamins & Mental Health: What’s the Connection?

B deficiencies are most commonly associated with birth defects and diseases such as pernicious anemia, pellagra, and ariboflavinosis. However, having a nutrient deficiency in one or more of the B vitamins can also increase one’s risk of developing depression. Vitamins B1 (thiamin), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B9 (folate), and B12 (cobalamin) have all been associated with depressive symptoms

So, what exactly does the research say about B vitamins and mental health? A 2019 systematic review and meta-analysis found that higher intakes of vitamins B1, B2, B6, and B12 were associated with a reduced risk of depression — particularly in women. Other research has linked deficiencies in vitamin B9 and B12 with an increased risk of depression and treatment-resistant depression, so much so that Mental Health America (MHA) recommends using folate as an adjunct therapy for depression due to its safety and effectiveness. 

As a registered dietitian nutritionist, I typically only see folate being recommended as an adjunct therapy by many medical providers in cases of treatment-resistant depression (aka those cases of depression that don’t seem to get better with antidepressants). However, I truly believe that everyone with any mental health condition should be tested for these B vitamin nutrient deficiencies AND genetic variations. Don’t worry! We’ll talk more about the genetic variations that affect mental health later in this article.

Furthermore, researchers at Victoria University in Melbourne have also looked at the effects of vitamin B on depression, finding that deficiencies in vitamins B1, B3, B6, B9, and B12 have all been linked to depressive symptoms such as irritability, apathy, fatigue, gastrointestinal distress, and restlessness. Additional research suggests that vitamin B5 and nutrient intake, in general, play a role in mood and mental health. More reasons to eat a nutrient-rich diet that’s full of good-mood foods and vitamins! 

Treating a B Vitamin Nutrient Deficiency

Having a B vitamin deficiency may sound a bit scary, but the good news is that these nutrient deficiencies that may affect your mental health can be addressed with the right foods and supplements. By identifying and treating one or more vitamin deficiencies, you could simultaneously improve your mental health!

For instance, recent research published in Human Psychopharmacology: Clinical and Experimental found that supplementing with high-dose vitamin B6 reduced anxiety in young adults. Supplementing with vitamin B9 is also shown to be promising as an adjunct therapy for improving depressive symptoms and making antidepressant treatments more effective. A similar effect can be seen with vitamin B12 supplementation in some individuals. 

As for the other B vitamins, a systematic review and meta-analysis of B vitamins concluded that supplementing with a combination of B vitamins has a positive effect on mood and stress reduction. However, as a registered and licensed dietitian, I recommend getting your B vitamins from food sources whenever possible instead of supplementing right away. If you do choose to supplement, do so under the guidance of a medical provider such as a doctor or registered dietitian nutritionist. And since many fortified whole grains, animal products, and plant foods (including some plant-based milk) contain plentiful amounts of B vitamins, it’s possible to get enough vitamin B from diet alone for most people. 

A few healthy sources of B vitamins include the following:

  • Leafy vegetables such as asparagus, spinach, and broccoli
  • Beans, lentils, and green peas
  • Whole grains
  • Eggs
  • Liver
  • Salmon
  • Mushrooms
  • Fortified nutritional yeast
  • Sunflower seeds and almonds

Certain medical conditions, age (people over 60), and medications can impair the absorption of B vitamins, increasing one’s risk of developing a nutrient deficiency. My functional lab testing add-on services for my coaching clients can help us to look for any vitamin and mineral deficiencies that may be affecting your mental health. In any case, I recommend having your medical provider test your B vitamin levels as this is a common nutrient that many providers will test for. Sometimes, I simply go to my local health fair to have these drawn!

Furthermore, some diets (like vegetarian and vegan diets) are lower in nutrients such as vitamin B12 — increasing one’s risk of becoming B12 deficient. Without adequate supplementation (taken daily or weekly), the risk of deficiency increases. 

Now, let’s move on to genetic variations that may cause B vitamin deficiencies and impair your mental health.

MTHFR Mutations & Vitamin B Supplementation

Did you know that several genetic variations are associated with an impaired ability to metabolize vitamins B9 and B12? While it’s possible to address vitamin B deficiencies with food alone, these include single-nucleotide polymorphisms (SNPs) in the following genes may require supplementation: 

  • MTHFR – Plays a key role in B9 metabolism. Impaired B9 metabolism affects methylation, detoxification, neurochemical balance, hormone balance, DNA synthesis, and cardiovascular health.
  • MTHFD1 – Plays a role in the methylation cycle and may impair the remethylation of homocysteine to methionine. This may increase the demand for choline as a methyl group donor, thus increasing the need for consuming more choline in the diet.
  • NBPF3 – C allele is associated with decreased serum levels of vitamin B6 due to more efficient clearance of vitamin B6 from the body. Prolonged B6 vitamin deficiency can lead to low vitamin B12 serum levels, thus negatively impacting methylation.
  • CUBN – Acts as a receptor for the intrinsic factor-vitamin B12 complexes and may play a role in autosomal recessive megaloblastic anemia
  • TCN1 – Plays a major role in the transportation of vitamin B12 into cells to be used by the body
  • TCN2 – Encodes for a protein that transports vitamin B12 from the bloodstream into the cells to be used by the body. Can cause B12 deficiency.
  • FUT2 – May indirectly interfere with the absorption of vitamin B12 due to disturbances in the gut microbiome and availability of intrinsic factor, which is important for vitamin B12 absorption.

Certain genetic mutations may even contribute to developing mental health conditions such as depression. This includes several variants in the MTHFR gene that have been linked to an increased risk of depression, bipolar disorder, and schizophrenia.

With genetic testing and nutrition counseling, you can uncover whether you have one or more SNPs in these genes so you’ll be able to choose the best B vitamin foods and supplements based on your unique genetic makeup. For me, finding out that I have SNPs in several of the genes mentioned above was an absolute game-changer for my mental health! I started supplementing due to the nature of the SNPs that I carry and noticed a big difference in my mental health and energy levels.

If you have MTHFR gene mutations and low B12 levels, cyanocobalamin (the form of B12 that’s most commonly used in supplements) won’t be the best form of B12 for you. Why? Well, cyanocobalamin is an inactive form of B12. And bodies with the MTHFR gene mutation, have impairments in the conversion of the inactive form of B12 to the active form. So, another form of B12, like methylcobalamin, may be needed instead. If you’re vegan or vegetarian, this is especially important as it’s harder to get optimal amounts of B12 from plant foods alone. If this is you, supplementation may be needed. 

As for treating or preventing a B9 (folate) deficiency, L-methyl folate supplementation may be needed in lieu of folic acid if you have MTHFR mutations as well. Again, this is due to the body’s impairment in turning the inactive form (folic acid) into the active form of folate. Of course, increasing your intake of foods rich in vitamin B9 is also important! Several of these foods include asparagus, avocado, broccoli, legumes, leafy greens, and eggs. 

Could a Nutrient Deficiency Affect Your Mental Health? I Can Help!

If you think you could be deficient in any of the B vitamins and/or you suspect other vitamin and mineral deficiencies could be affecting your mood and energy levels (like vitamin D, magnesium, and omega-3 fatty acids), I can help.

Whether you choose to enroll in collective or private coaching here at The Fulfilled Fork, we’ll use nutritional genetic testing to create a diet and lifestyle plan that supports your unique body and DNA. Together, we’ll look at the whole picture of factors that affect mental health to create a personalized course of action so you can start feeling more like yourself again.

Apply for coaching today and see for yourself how changing your diet and lifestyle can help to improve your physical health AND your mood! 

Ready to nourish your mind and body for a healthier and happier life? Start by learning more about nutritional genetic testing or collective or private coaching.



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Howdy! I’m Haley. A registered dietitian nutritionist, yoga teacher, personal trainer, and holistic mental wellness coach on a mission to help you transcend the struggle, stress, and suffering that life can bring. I’ve lived through it and discovered a path to feeling amazing in my mind, body, and soul. Now, I want to help you to live your most fulfilled life too through evidence-based nutrition and lifestyle practices!

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